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PID Controller C++

Creating a PID controller in C++ involves implementing a class or a set of functions to handle the control logic. A PID controller is commonly used in control systems to regulate a process by adjusting a control input based on the error (the difference between the desired setpoint and the actual process variable). Here’s a simple example of a PID controller in C++:

#include <iostream>

class PIDController {
    PIDController(double kp, double ki, double kd)
        : kp_(kp), ki_(ki), kd_(kd), prev_error_(0), integral_(0) {}

    double calculate(double setpoint, double process_variable) {
        double error = setpoint - process_variable;
        integral_ += error;
        double derivative = error - prev_error_;
        prev_error_ = error;
        double output = kp_ * error + ki_ * integral_ + kd_ * derivative;
        return output;

    double kp_;          // Proportional gain
    double ki_;          // Integral gain
    double kd_;          // Derivative gain
    double prev_error_;  // Previous error
    double integral_;    // Integral of errors

int main() {
    // Example usage of the PID controller
    PIDController pid(0.5, 0.2, 0.1); // You can adjust these gains accordingly
    double setpoint = 50.0; // Desired setpoint
    double process_variable = 0.0; // Initial process variable

    for (int i = 0; i < 100; ++i) {
        double control_output = pid.calculate(setpoint, process_variable);
        // Simulate the process by updating the process_variable
        // In a real system, this value would come from a sensor
        process_variable += control_output;

        std::cout << "Iteration " << i << ": Setpoint=" << setpoint
                  << ", Process Variable=" << process_variable
                  << ", Control Output=" << control_output << std::endl;

    return 0;

In this example:

  • The PIDController class takes the proportional (kp), integral (ki), and derivative (kd) gains as parameters in its constructor.
  • The calculate method computes the control output based on the current error, integral of errors, and derivative of the error.
  • In the main function, we create an instance of the PID controller and use it to control a simulated process variable.

Remember to adjust the PID gains (kp, ki, and kd) according to your specific control system requirements. Additionally, in a real-world application, you would replace the simulated process variable update with actual sensor readings and control of a physical system.


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